Electrical apparatus and circuit.



A. L..SOHM.

ELECTRICAL APPARATUS AND CIRCUIT.v

APPLIlcATloN FILED APR.22, 1912.

1,138,991. Patented May 11, 1915.

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@wn/66665: mn/507 v i i z v v @Zorn/@75 UNITED STATES PATENT onnion.

ALFRED L. SOI-IM, OF CHICAGO, ILLINOIS, ASSIG-NOR TO SOHM ELECTRIC SIGNAL @t RECORDING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION vOE ARIZONA.

ELECTRICAL APPARATUS AND CIRCUIT,

Application med April 22, 1912.

larly concerned with make-and-break mechamsm.

Although my invention may be adapted to various other uses, as Will be apparent to those skilled in the art, I contemplate its employment especially in connection with a time keeping system or other organization wherein it is desirable to closeA an electric vcircuit for a short period at intervals. Thus,4

in an organization controlled bv a masterclock, which closes an electrical circuit at regular intervals, it is desirable, in the operation of a secondary clock, to have the periods during Which current is supplied to the secondary clock .as short as possible. In this Way the batteries are saved and their lives are lengthened, and the amount of attention necessary is' reduced to a minimum.

It is the object of mv invention to provide 'means for intermittently closing the circuit of the secondary clock and to provide such means Which will close the circuit for a very short period -of time. I have found by eX- periment that the particular apparatus which I providesecures the proper result and is able to close'the .circuit for such a short space of time as ond-tenth of va second, or even less. .Heretofore 'it has been impossible to provide contact mechanism which would reduce the closed period to less than a second and it will be seen that by the use of my invention practically nine-tenths of the current is saved. It is obvious that accuracy ofoperation is very important and to this end I have provided various features for preventing unintended operation and repetition of contact by momentum, These'various features are all combined by my improved contact mechanism and the particular manner in which the various parts are connected up in circuit is also of importance. It has heretofore been attempted to lessen the time of contact by improving the contact Specification of Letters Patent.

Patented May 11, 1915.

Serial N o. 692,299.

mechanism of the master-clock itself, but to no avail.- I secure the advantages hereinbefore pointed out by placing my improved contact mechanism under the control of electromagnets which, in turn, are controlled by the master-clock mechanism. The contact mechanism controls an entirely inde-- pendent circuit and it Will be seen that in this Way the length of time during Which the second circuit is closed is not at all dependent upon the time that the rst circuit is closed. Thus, the master-clock may be of any ordinary construction and the particular length of time during Which the first circuit is closed is immaterial. In order to save the current in this first circuit, I make the electromagnets referred to of high 'resistance, the elds produced, however, being sufficient to operate the contact mechanism. The peculiar construction of, thev contact mechanism determines the time during which the second circuit is closed.

My invention is illustrated in the accompanying drawings, in Which- Figure 1 is an elevational View of the locking relay .of myinvention, the primary clock, the secondary clock, the batteries, and the condensei's being shown diagrammatically and being diagrammatically villustrated as connected up in circuit; and

Fig. is a plan view of the relay.

The parts of the relay are mounted upon a magnetic frame piece comprisingthe base 3 and the L-shaped member 4 secured thereon by yany suitable means. The L-shaped magnetic member has its short side vertical and secured at its end to the top of the' basef piece, and the long side is parallel With the base piece. An iron core is secured to the short part of the L-shaped member and a Winding 6 is mounted upon this core. The

armature 7 is pivoted at 8 to the forward end of the base 3 and it is provided with a hook 9 which .engages the underside of the base piece `in order to limit the drop thereof. It Will be clear that when the winding 6 is energized the armature 7 Will be drawn up to the core 5 and the magnetic circuit Will be-closed. At the rear end of the base piece I secure the iron core 1Q upon which the Winding 11 is mounted.l An armature lever 12 is pivoted at 13 in keepers 14, 14 secured upon the top of the member 4 and the rear arm of this lever carriers the armature 15 which 'is thus disposed in proximity 11,0

to the end of the core 10. The other arm of the lever 12 extends forwardly beyond the frame piece 4: and is provided with a downwardly extending hook 16, the back of this hook being chamfered back as illustrated. The parts are so disposed that when the armature 7 is drawn up it will engage the front of the hook 16, this front being really a cam surface, and will raise that arm of the lever 12. lVhen, however, the armature 7 is brought all the way up,- the forward arm of the lever 12 drops into place and holds the armature` 7 in the raised position whether or not the winding 6 is energized. The forward arm of the lever 1,2 may be heavier than the rear arm so that the lever may be held in its normal position by gravity, or a spring shown in dotted lines at 17, may be provided to secure this action.

Toward the rear of the member 4 an insulating block 18 is mounted by means of screws 19, 19, and three springs 20, 21 and 22 are mounted in this insulating block so as to be insulated from each other. For con venience I shall refer to the spring 20 as the back spring, the spring 21 as the intermediate spring, and the spring 22 as the cam spring. The spring 22 carries the cam member 23 at its forward end. This cam surface is flat and at its end is bent back as shown at 24 so as to assist in guiding the armature to the cam at 23. A hump 25 is provided at the rear end of the cam surface 23, all for a purpose to be described presently. The spring 22 carries the contact member 2G, the spring 21 carries the Contact member 27, and the spring l20 carries the contact members 28 and 29 for cooperation with the contact members 26 and 27 respectively. It will be seen that normally the contacts 26 and 28 are separated while the contacts 27 and 29 are closed together. Vhen the winding 6 is energized, the armature 7 will be drawn 'up into engagement with the cam surface 23 and a1- most immediately the contacts 26 and 28 will be brought into engagement. These contacts will remain in engagement during the entire travel of the armature 7 under the cam. surface 23, but when the armature 7 has reached the hump 25 the springs 2O and- 22 will be raised suddenly, together, so as to break the contact at 27, 29. The length of time during which the armature 7 engages the cam surface 23 determines the i length of time during which the springs 22 and 21 are electrically connected together. This circuit is established practically as soon as the armature 7 engages the surface-23 and is broken just as. soon as the armature 7 hits the hump.

The contact wheel of the master clock, which is time-controlled, is Shown at M, this contact Wheel being of bone or other insulating material and having a notch n which Liesbet may coperate with projections on the contact springs s, s. These springs are connected together and to one pole of a battery B. The other pole of this battery is connected with one terminal of the winding 11 and also with one terminal of the winding G. The other terminal of the winding 11 is connected with the stationary contact c and the other terminal of the winding 6 is connected with the stationary contact c. lt will thus be clear that when the spring e is down upon the contact c, the magnet 6 will be energized to attract the armature 7 and that when the spring s contacts with the contact c, the magnet 11 will be energized to release the armature 7. Condensers C, C are connected in shunt of the con tacts of the master-clock and a condenser C is connected in shunt of the springs 21 and 20 in order to eliminate sparking.

A secondary clock S is connected in series of the battery B across the limbs l and l which entend from the springs 21 and 22 respectively. It will be clear that any number of secondary clocks may be bridged across these limbs and be subject to the control of the contact mechanism.

As bcforestated, the windings of the electromagnets G and 11 are high wound so as to save the current from the battery B. The contact wheel M being time-controlled, it will intermittently and regularly close the circuit between the spring s and the stationary contact c. This will energize the electromagnet 6 and the armature 7 will be drawn up. This attraction of the armature is very quick indeed and the length of time after it rst engages the surface 23 of the cam spring and when it engages the hump 25 thereof is very short. As before stated, I have found by experiment that I can reduce this time to less than one-tenth of a second. When the armature 7 engages the surface 23, the spring 22 is raised so that the Contact 26 engages with the contact 28 on the spring 20 and this engagement continues until the armature, in its movement in the direction of the arrow a, reaches the hump 25. Then, suddenly, the two springs 22 and 2O are raised so that the contact 29 on the spring 20 leaves the contact 27 on the spring 21. The spring 21 is prevented from following the spring 2() by reason of its engagement with the insulating pin 30 on a post 31 secured on top of the frame piece. It will be clear that while all three springs are in electrical engagement, the circuit of the secondary clocks is closed, and only then. The secondary clocks may be of any respective construction and it will be seen that the amount of current re uired for their operation is very small indeed. It will furthermore be noted that it is unimportant how long the master-clock circuit is closed since all that is required is an impulse to bring the armature 7 up. It is heldmechanically and later on, by reason of the operatlon of the springs c and s and the consequent energization of the electromagnet 11, is re leased. It will be noted that the lever 12 carries the insulating pin 32 and that when the armature 15 is attracted to the core 10, this insulating pin keeps the spring 20 out 'of range of the spring 22 and the contact carried thereby. This prevents any contact upon the recession of the armature 7. The locking feature of the device effectively prevents double contacting which so frequently occurs in clock circuits. y

I claim as new and desire to secure by Letters Patent: A

f 1. In combination, a pair of contact springs, a third spring common to them, a normally open secondary clock circuit controlled by,` said pair, a source of current in said clocky circuit, an electromagnet, an armature arranged to make a passing common Contact between said springs whereby impulses of uni-directional current are sent through said `secondary clock circuit, and a master clock controlling said electromagnet.

2. In combination, a pair of contact springs, a third spring common to them and normally in contact with one of them, a normally open secondary clock circuit includlng a source of current controlled by said pair, an electromagnet,l an armature arranged to close the open contact and open the closed contact by the attraction of said armature to send impulses of uni-directional current, and a master clock controlling said electromagnet.

3. In combination, a pair of contact springs, a third spring common to them, a secondary clock circuit controlled by said pany/an electromagnet, an armature therefor arranged to make passing common contact between said springs, means for mechanically locking said armature in its raised position, a second electromagnet, means controlled by said second electromagnet for releasing said armature, and a master clock controllingl said electromagnets.

4. In combination, a pair of contact springs, a third spring common to' them, a

being normally out of contact, a third spring normally in contact with one of said springs, an electromagnet having a circuit controlled by the .pair of contacts of said master-clock, an armature for said electromagnet, said armature bringing the three springs momentarily into contact to close the secondary clock circuit.

6. In combination, a pair of normallyopen contact springs, a third spring in contact with one of said springs, an electromagnet for bringing all of said springs momentarily into contact, `a secondary clock circuit including a single source of uni-directional current controlled-by said springs, and a master-clock circuit controlling the energization 'of said electromagnet.

7. In combination, a master-clock circuit, a secondary clock circuit, an electromagnet having an armature, a pair of springs for said secondary clock circuit controlled by the electromagnet, a third spring making momentary contact with both of said springs when the armature of said electromagnet is attracted, and a second electromagnet having a circuit controlled by the master-clock, said second electromagnet releasing the armature of the first electromagnet Without causing contact between said pair of springs and said third spring.

In witness whereof, I hereunto subscribe;

my name this 19th day of April, A. D. 1912.

ALFRED L. SOHM. Witnesses: s T. D. HEYL, ARTHUR H. Bonfrrcrrnn. 

